The present invention relates to computer-aided reality systems.
Modern “virtual reality” apparatus typically include video and audio signal generators that provide signals to a headset in accordance with instructions received from a controller. The headset projects a near field image inches away from the viewer, typically completely occupying the field of the vision of the viewer's eyes. Most such virtual reality systems alter the view presented to the viewer in response to the position of the viewer's head, as sensed by the headset, such that the view changes in much the same manner that a far field image received by the human eye would vary. Other system have presented an image to a viewer by scanning the viewer's eye or eyes with a modulated beam of light. Such systems directly present the image to the viewer's retinas, thereby advantageously obviating the need for either far field or near field projection screens.
U.S. Pat. No. 6,454,411 discloses an apparatus for directly projecting an image onto a retina includes an optical source for generating a light beam to be focused on a retina. A projection device sweeps the light beam along the retina in an ellipsoidal pattern such that a higher spatial concentration of light pixels impinge a central portion of the retina than a peripheral portion thereof. A controller is coupled to the optical source and the projection device for modulating the light beam such that a higher temporal concentration of light pixels impinge a central portion of the retina than a peripheral portion thereof.